Traditional muffler designs have paid little attention to the importance of the inlet and outlet locations relative to obtaining maximum attenuation from a given muffler volume. In the past, two standard approaches have typically been used. In the first, the inlet and outlet have been axially aligned as in a straight-through expansion chamber, a plug section or a resonator. The second approach has been to offset both the inlet and outlet along a diameter of the muffler body, as used in a so-called "pass-type" muffler. However, the positioning of the inlet and outlet has been primarily for convenience of construction and adaptation to engines, as opposed to obtaining maximum sound attenuation.